1. Field of the Invention
The present invention relates to an apparatus for a photolithography process for manufacturing a semiconductor device, and more particularly, to a photolithographic apparatus in which a plurality of steppers are in parallel connected to one coater/developer.
2. Description of the Related Art
In general, a semiconductor device is manufactured through various processes. A photolithography process for transferring a micropattern to a semiconductor wafer is necessary for manufacture of the semiconductor device.
The photolithography process includes processes of coating, exposing and developing. The coating process is for forming a photoresist film on the semiconductor wafer. The exposure process is for irradiating light such as UV-ray on the photoresist film of the semiconductor wafer through the photomask after aligning semiconductor wafers where the photoresist film are formed and photomasks where micropatterns to be transferred are drawn. The development process is for developing a photoresist film of the semiconductor wafer where the exposure process is completed, to form a desired photoresist pattern.
However, a system for arranging apparatuses for performing the photolithography process is largely divided to two-types.
The one type is a stand-alone system in which a coater, a stepper and a developer are independently used without connection.
The other type is an in-line system in which one coater/developer and one stepper are in series connected.
In the stand-alone system, since flow of semiconductor wafers is not automatic, the wafer flow among the coater, the stepper and the developer must be controlled by an operator. Accordingly, the stand-alone system requires manual operation, a speed for processing the semiconductor wafers is low and the semiconductor wafers are contaminated due to particles. Thus, the in-line system is widely used to improve the efficiency of the photolithography process.
FIG. 1 shows a conventional photolithographic apparatus in which a coater/developer 10 and a stepper 20 are in series connected.
Referring to FIG. 1, the coater/developer 10 performs processes of coating and developing. The stepper 20 performs an exposure process.
FIG. 2 is a layout diagram showing an example of the conventional photolithographic apparatus of FIG. 1 arranged in a clean room.
Referring to FIG. 2, first through twenty-fourth photolithographic apparatuses are arranged in the clean room. Here, in the first photolithographic apparatus, a first coater/developer CD1 and a first stepper ST1 are in series connected, and in the second photolithographic apparatus, a second coater/developer CD2 and a second stepper ST2 are in series connected. Also, in the twenty-fourth photolithographic apparatus, a twenty-fourth coater/developer CD24 and a twenty-fourth stepper ST24 are in series connected.
At this time, the first and second wafer suppliers 50 and 60 supply first and second automatic guide vehicles 30 and 40 moving on first and second rails 70 and 80 with the semiconductor wafers, respectively. Subsequently, the first automatic guide vehicle 30 supplies one of first through twelfth photolithographic apparatuses with the semiconductor wafers through one of the first through twelfth coater/developers CD1 through CD12. Also, the second automatic guide vehicle 40 supplies one of thirteenth through twenty-fourth photolithographic apparatuses with the semiconductor wafers through one of the thirteenth through twenty-fourth coater/developers CD13 through CD24. Subsequently, the first through twenty-fourth photolithographic apparatuses expose and develop the received semiconductor wafers, and then transmit the exposed and developed semiconductor wafers to the first or second wafer suppliers 50 and 60 through the first and second automatic guide vehicles 30 and 40. At this time, the flow of the semiconductor wafers on the first and second rails 70 and 80 is controlled by first and second cell control rooms 90 and 100, respectively. Here, reference numeral 10 indicates a third cell control room for controlling the flow of the semiconductor wafers on a neighboring rail (not shown).
However, in the conventional photolithographic apparatus of FIGS. 1 and 2, since each of the steppers requires coater/developers, respectively, a space of clean room is not effectively used and excessive equipment investment cost is required. Also, since the speed of processing the semiconductor wafers in the stepper is lower than that in the coater/developer, a speed of processing wafers in the photolithographic apparatus is reduced. Further, when the stepper or the coater/developer temporarily stops operating due to defect or preventive maintenance, the operation of the photolithographic apparatus is stopped. This is because the stepper and the coater/developer are in series connected. Therefore, equipment operating rate is reduced.